1. Field of the Invention
The present invention relates to a shaft-fixed spindle motor using a fluid dynamic bearing and a method of manufacturing the spindle motor.
2. Background Art
In recent years, a spindle motor for use in a hard disk driving apparatus or the like is requested to realize further reduction in cost, and excellent reliability and durability.
FIG. 13 shows a conventional spindle motor. In the spindle motor, a pair of conical members 310 are provided so as to be apart from each other in the axial direction around a shaft 204, and dynamic bearings are constructed in minute gaps between the pair of conical members 310 and sleeves facing the pair of conical members 310. An oil reservoir 380 is constructed in a space wider than the minute gap, between a shield member 328 fixed to the sleeve and the conical member 310. The outer peripheral surface of the shaft 204 and the inner peripheral surface of the shield member 328 are disposed so as to be close to each other. Oil is applied to the inside of the dynamic bearing via a through-hole 350 in the shield member 328.
However, in the case where the minute gap and the space wider than the minute gap mixedly exist in the motor as described above, it is sometimes difficult to assemble the motor. Specifically, in the spindle motor of FIG. 13, for example, in the case of applying oil to the inside of the dynamic bearing in the environment that the pressure in the periphery is reduced, gas in the dynamic bearing is exhausted from the through-hole 350 and a relatively small region between the shaft 204 and the shield member 328 to the outside of the motor. Consequently, it takes time to exhaust the gas so that workability is not so high. When oil is applied in a state where air bubbles remain in the dynamic bearing, at the time the air bubbles are exhausted from the inside of the dynamic bearing to the outside of the motor, the oil is also leaked together with the air bubbles to the outside of the motor, and the space in the hard disk driving apparatus, which has to be kept clean becomes dirty.